In the study nano particles were studied. Nano particle means that at least one dimension of the particle is under 100 nm. Also effects of those particles added to paper structure with biopolymers were studied. Target was to determine, how these additions affect primarily paper formability but also other properties. The study was a part of Namewood-project. An essential hypothesis is that if there is some benefit available with used particles and polymers, it shows in the results despite the way of the addition. Another hypothesis is that particles and polymers drift to the fibre crossing sections directed by surface tension forces. The study is divided into four parts: literature survey, preliminary tests, main tests and the complementary tests. Literature survey studies what nanoparticles are and how they differ from conventional particles. Also the applications and health effects of nanoparticles are studied. Previous Namewood results were considered with a view of selecting the right particles for this study. Nanoparticles have an enormous specific area so the role of surface phenomena increases substantially. Nanoparticles have been used among others in polymer composites and to oncrease the dimension stability of wood. In paper industry, nanoparticles are used to enhance retention and drainage. Based on the results of the study it seems that no essential benefits are gained with the studied biopolymer and particle additions. Neutral starch improved Scott bond even more than cationic starch and the smaller addition of particles it improved bonding even more. However, the major addition did not improve other paper properties than bending stiffness.